Key Takeaways
Cod liver oil and fish oil both deliver omega-3 fatty acids, but they differ significantly in source, vitamin content, and formulation behavior. Cod liver oil is extracted from the liver of Atlantic cod and naturally contains vitamins A and D, while general fish oil is typically pressed from the body tissue of species like tuna, mackerel, and sardines with a higher concentration of EPA and DHA. Brands developing omega-3 products should evaluate both as complementary ingredients, and partnering with a premium cod liver omega 3 oil manufacturer that also supplies tuna oil gives formulators full flexibility.
Marine oils sit at the center of the global omega-3 supplement category, but cod liver oil and general fish oil are often treated as interchangeable when the reality is they are not.
Essential fatty acids are provided by both, and they both have extensive nutritional histories. The differences lie in the fish’s oil source, its inherent nutrients, and its performance in the final product.
For brands sourcing marine oils at scale, the choice between cod liver oil vs fish oil, or working with both, affects everything from label claims to encapsulation format. Here's how they compare.
What cod liver oil and fish oil actually are
Cod liver oil is extracted specifically from the liver of Atlantic cod. Because the liver stores fat-soluble vitamins, the finished oil naturally contains vitamins A and D alongside its omega-3 fatty acid profile.
Fish oil, more broadly, is pressed from the body tissue of oily fish species including tuna, sardines, anchovies, and mackerel. These oils are concentrated for their omega-3 content, particularly EPA and DHA, without the naturally elevated vitamin A and D content that comes with liver-based extraction.
Source differences
Between cod liver oil and fish oil, what is the difference and which is better often starts with the source itself:
- Cod liver oil is sourced from cod liver only, driving its distinct vitamin A and D content
- General fish oil is sourced from whole body tissue of multiple oily fish species
- Tuna oil is a subset of fish oil, extracted from tuna as a co-product of tuna processing, notable for its DHA-rich profile
- Co-product utilization is a growing formulation preference, using raw material that would otherwise go to waste
Though both oils undergo refining and stabilization, their initial nutritional content is determined by the chosen raw material.
Nutritional composition
- Cod liver oil contains EPA and DHA plus naturally occurring vitamins A and D
- Tuna oil is typically high in DHA, making it particularly relevant for infant formula, cognitive health, and eye health formulas
- General fish oil from sardine, anchovy, and mackerel blends often carries a more balanced EPA-to-DHA ratio for cardiovascular formats
The nutritional aspect is key for label claims, allowing cod liver oil supplements to boast natural vitamin A and D, whereas concentrated tuna oil DHA supplements usually highlight benefits for brain, eye, or infant health.
Vitamin content
Cod liver oil differs most clearly regarding vitamin content. Because it is extracted from the liver, cod liver oil naturally contains vitamins A and D at meaningful levels, which is why it has been used historically to address deficiencies related to bone health, immune support, and vision.
In contrast, fish oil from body tissue does not naturally carry the same vitamin load. If a fish oil product lists vitamin A or D on the label, those vitamins are almost always added separately during formulation.
For formulators, this distinction is important to consider as it affects both cost structure and consumer positioning.
Omega-3 content
Cod liver oil delivers a moderate concentration of EPA and DHA together with its vitamin content. However, tuna oil, and refined fish oils more generally, can be processed and concentrated to deliver much higher omega-3 percentages per gram.
For brands designing high-potency cardiovascular or brain health softgels, concentrated tuna oil or blended fish oil often wins on dose-per-capsule efficiency. Brands leading on whole-food, natural, or traditional wellness positioning will see cod liver oil's intact vitamin profile as the bigger differentiator. Neither is objectively better, as the correct choice depends on the finished product.
Consumer applications
Cod liver oil is commonly formulated into children's nutrition and family wellness products, immune, bone, and vision health softgels, and traditional wellness lines emphasizing natural vitamin content.
Tuna oil and general fish oil are commonly formulated into high-potency omega-3 cardiovascular softgels, infant formula via high-DHA tuna oil, cognitive health and prenatal nutrition, and sports nutrition and joint health blends.
Premium brands frequently market both types, designating cod liver oil as their legacy product and concentrated fish oil as their performance-oriented product.
Formulation considerations
Beyond nutritional profile, the oils’ formulation and how they perform matter just as much. Several factors play into a proper formulation:
- Oxidation stability and shelf life
- Sensory profile including odor and aftertaste
- Fit with softgel, liquid, emulsion, or gummy formats
- Regulatory positioning for infant nutrition and clinical applications
- Full traceability from raw material to finished ingredient
For brands working at commercial volume, having the right ingredient partner is as significant as the ingredient itself.
Why partner with Thai Union Ingredients
Thai Union Ingredients operates as the B2B marine ingredients arm of Thai Union Group, supplying both tuna omega-3 oil and cod liver omega-3 oil to brands worldwide:
UniQ®OMEGA Tuna Omega-3 Oil delivers high-purity DHA derived from 100% traceable tuna, refined for superior sensory profiles and stability across softgel, liquid, and emulsion formats. UniQ®OMEGA Cod Liver Omega-3 Oil offers a natural source of vitamins A, D, and omega-3s for immune, bone, and vision health formulations where intact nutrient content is the differentiator.
Behind both products sits a pharma-grade oil refinery in Rostock, Germany, supported by our Omega-3 Centre of Excellence in Samut Sakhon, Thailand. Our vertically integrated supply chain provides full traceability from sea to shelf, aligned to SeaChange® 2030 sustainability commitments and backed by formulation expertise for brands scaling from pilot to commercial volume.
Choosing the right marine oil for your product
Cod liver oil vs fish oil isn't really a versus question at the ingredient sourcing level. The selection depends on the intended buyer, health benefits, and product type for the final item, as both are vital for a robust marine nutrition strategy.
At Thai Union Ingredients, we approach the marine oil category from a fully vertically integrated position, with sourcing, refining, and formulation support housed under one supply chain. Through our UniQ®OMEGA tuna and cod liver oil lines, pharma-grade refining in Germany, and full traceability aligned with SeaChange® 2030 commitments, we offer brands access to both categories with quality, ease, and assurance.
Explore Thai Union Ingredients today as your premium tuna omega-3 oil supplier and premium cod liver omega-3 oil manufacturer. We offer a full marine oil portfolio and formulation support built to move your next product forward.
References:
Thai Union Ingredients' Omega-3 Centre of Excellence is open for business. Retrieved January 15, 2026, from https://thaiunioningredients.com/news/thai-union-ingredients-omega-3-centre-of-excellence-is-open-for-business
Thai Union Sustainability Report 2025. Retrieved January 15, 2026, from https://www.thaiunion.com/uploads/Sustainability_Report_2025_en_1.pdf
Frequently Asked Questions About Cod Liver Oil vs Fish Oil
Q: Cod liver oil vs fish oil, what is the difference and which is better?
A: Cod liver oil is extracted from the liver of Atlantic cod and naturally contains vitamins A and D alongside omega-3 fatty acids. General fish oil is pressed from the body tissue of oily fish like tuna, sardines, and anchovies, and typically delivers higher concentrations of EPA and DHA. Neither is objectively better; the right choice depends on the finished product, target health claim, and consumer positioning.
Q: Does cod liver oil have more omega-3 than fish oil?
A: Not usually. Fish oils, including tuna oil, typically deliver a higher percentage of omega-3 fatty acids per gram than cod liver oil. Cod liver oil's advantage is its naturally occurring vitamin A and D content, which is not present at meaningful levels in body-tissue fish oils.
Q: Which is better for children, cod liver oil or fish oil?
A: Cod liver oil has a long history in children's nutrition thanks to its natural vitamin A and D content, but dosing needs to be managed carefully because vitamin A can accumulate. High-DHA tuna oil is often used in infant formula and children's cognitive health products where a concentrated DHA profile is preferred without the added vitamin load.
Q: Where can B2B buyers source both cod liver oil and fish oil at scale?
A: At Thai Union Ingredients, we supply both UniQ®OMEGA Cod Liver Omega-3 Oil and UniQ®OMEGA Tuna Omega-3 Oil through a vertically integrated, fully traceable supply chain. This is backed by pharma-grade refining in Rostock, Germany and formulation support through our Omega-3 Centre of Excellence in Samut Sakhon, Thailand.